Fluid displacement device



H. sc'zl-INEIDI-:Rr 2,028,414 FLUID DISPLACEMEM- DEVICE Filed May 19,193s 2 sheets-sheet 1 ATTORNEY.

Jan. 21, 1936A H. SCHNEIDER 2,028,414

l vFLUID DISPLACEMENT DEVICE Filed May 19, 1955 2 Sheets-Shoe?l 2INVENTOR /vE/N/Q/cf/ 5CH/15mm BY g; U

ATTRNEY.

Patented Jan. 21, 19,36

y FLUID DISPLACEMENT DEVICE Heinrich schneider, Beloit, wis.. assignmfoFan-- banks, Morse & Co., Chicago, Ill., a corporation of IllinoisApplication May 19, 1933, Serial No. 671,820

7 Claims.

This invention relates to improvements in fluid displacement devices,particularly air compressors of the so-called Roots type', for internalcombustion engines and the like. More specifically, the invention isdirected to improvements which minimize certain objections heretoforeprevailing in compressor operation, such as, for example, suction andcompression noises.

An object of the present invention is attained in an improved compressorof the type noted, in which the air inlet passages to the impellerelements are of a tortuous trend from the inlet ports to the compressionchamber, whereby substantially to reduce the noise formerly incident tothe suction of air through the inlet ports and passages. y

Another object is attained in an improved compressor of the type noted,in which the compression chambers and outlet passages are so formed andrelated in assembly as to provide a gradual pressure equalization of theair in proceeding to a receiving chamber, whereby the objectionablenoises of compression are considerably lessened. l l

Further objects and advantages will appear from the followingspecification, and from the appended drawings, in which:

Fig. 1 is a longitudinal sectional elevation of a compressor as viewedalong line I-I of Fig. 2 and Fig. 2 is a transverse sectional elevation,as taken along line 2-2 in Fig. 1.

Referring, now, to the drawings by numerals of reference, 5 designates,generally, a compressor assembly embodying improvements presently tobedescribed. The assembly presently exemplifying the invention includes agear case section 1, and separate impeller housing sections 9 and I0.The housings or casing sections are preferably secured in assembly bythrough-bolts I2 (Fig. 2). It is, of course, understood that withinpractical and mechanical limits, any number. of individual impeller andhousing sections and associated assemblies, such as the housingassemblies 9 and I0, may be employed in the compressor assembly. -In theapplication of the compressor or blower as a source of scavenging air toan internal combustion engine, for example, a part of the frame of whichis shown at I3 (Fig. 2), each engine cylinder may be supplied from asingle impeller section, or several cylinders may be supplied from oneimpeller assembly. The

angular setting of the impeller elements presently to be described, inadjacent impeller assemblies, is, in such case, preferably in accordancewith the timing of the engine cycle of operation. Ex-

cept for this, the individual impeller assemblies and housings are ormay be substantially alike in construction and operation. Hence, thedetails of only one of the impeller assemblies need be given in thefollowing description, the same 5 reference numerals applying to likeelements in each of the several displacement units.

Impeller shafts I4 and I5, disposed in spaced relation within theimpeller casings 9 and I0, and extending substantially the length of the10 compressor, are each journalled at one end in a.v portion I6 of theend Wall I1 of the case section III. vThe opposite ends I8 and I9 ofshafts I4 and I5 respectively, are journalled in a wall portion 2li ofgear housing 1. Driving gears 2l and 15 22, resiliently coupled througha torsion spring 23, are preferably journalled in an enlarged end wallportion 24 of the gear casing 1, substantially as illustrated in Fig. 1.The gear 2l may be coupled, either directly or indirectly, to the crank20 shaft of the engine (not shown) to which the blower is to be applied.The gear 22 preferably engages a pinion 25 secured upon the endvl8 'ofshaft I4, for driving the shaft. The shafts I4 and I5 are coupled foropposite rotation vat the 25 same rate of speed, through'like gears 26and 21 disposed on the shaft ends I8 and I9 respectively. Referring nowto Fig. 2, the casing 9 provides a pair of compression chambers 30 and3l within which impeller elements 32 and 33 rotate, re- 30 spectively.These chambers are each of substantially cylindrical form, but areoverlapping, in the sense that the central part of the displace-- mentspace is common td both chambers. The impellers may be of conventionalform, and are 35 preferably secured to the shafts by splinedconnections, as appears in Fig. 2. An air 'inlet port 34, substantiallybelow the compression chambers,

is provided for each of the impeller assembly sections 9 and I0. Acurved inlet passage 35 40 extends from the port 34 to an internal inletport 36, supplying air to the compression chamber portions 30 and 3|.The passage is given a tortuous trend due in part to the provision of abaiiie element 38 extending within the passage, 45 adjacent the inletport opening 34. A slotted grid or grille member 39 disposed over eachinlet opening 34, serves as a means for breaking up the entering airstream. Passages 40 and 4I through portions of the dividing wall 42between 50 the casing sections 9 and II), aid in, equalizing thequantity of air delivered to the several compression chambers. Thetortuous inlet passages, equalizing passages, and the grid' member 39collectively serve to divide and deiiect the incoming air streams to anextent materially td reduce the objectionable suction noises heretoforeprevalent in compressors of the present general design, in whichsubstantially unitary or undivided and unidirectional streams of airwere drawn in by and presented td the impellers.

Outlet passages 44, 45, 48, 41 and 48, through a portion oi' thecompression chamber wall opposite the wall containing the chamber inletopening 36, communicate with a chambered compressed air receiving tting50, which is or may be in direct communication with a chamber 5| of anengine or other machine to which the compressor is applied. When theblower is utilized to supply scavenging air to a twol-cycle engine, thechamber 5I may consist of a receiver or manifold with which isconnected. the scavenging air ports. It will be noted that one group orseries of passages 44 through 48, is provided for each displacementchamber 30 or 3|, and that these groups are relatively reversed inposition, the passages o'f each group being graduated in area from thecenter to the margins of an outlet grille 5IA. This form and arrangementof passages has been found preferable, in practice. However, thepassages may be of uniform size, i1 desired.

In the older prevailing forms of blowers oi the same general type, thepartly-cylindrical wall 52, defining each of the compression spacesconstituted by chambers 30 and 3|, extended substantially from the pointX through the point Y to point Z, (Fig. 2) or through an arc usually of180- or less, the wall portion containing the passages 41 and 48, havingbeen heretofore unapertured, as in the presently improved construction,except for a single large opening. In the operation o'f the blower,therefore, as soon as the impeller 32 y `closed off the suction inlet tochamber 30 upon passing po'int X in the direction of rotation indicatedby the arrow (Fig. 2), the compression chamber 30 was placed in directcommunication with the receiver 50, and a sudden equalization ofpressure in the two chambers occurred. As a result of such suddenpressure equalization, objectionable vibration and compression noiseswere set up. Hence, the present improved compressor serves objectivelyto eliminate the above noted objectionable features of operation. In theimproved compressor, the wall portions 52 are extended inwardly orcentrally beyond points X and Z,'vto points a and b, respectively, andhence substantially beyond a diametral plane transverse of the case,which plane, for purposes of present reference, may be considered normalto the plane common to both impeller axes, and being plane I--I of Fig.2. The hereinabove described passages 44 to 48 are provided in thegrille portion 5|A, which may be a part of the wall 52, adjacent thechamber 50. In the construction as presently modiiled, the impeller 32cuts off the inlet near point a, the compression chamber 30 is graduallyopened to the receiver chamber 5U, as the extremity of the impeller suc,

curs between the chamber 3| and receiver 58, due

to the provision of the companion group of grille openings therebetween.

While the novel features incident to only one of the displacementchambers, have been described, it will appear from the drawings (Fig.2), that both of the chambers 30 and 3i are similarly constructed andsymmetrically disposed.

The present improvements in a compressor of the type noted, serve verymaterially to reduce the heretofore objectionable operating noises, andfurther result in a more efficient and smoother running machine. It mayhere be indicated that a blower embodying the present improvements, ischaracterized by a minimum of vibration, resulting from the embodimentof principles having the effect of noise suppression; further that theimproved machines are highly eilicent in service.

It is to be understood of course, that the invention is not to belimited to the presently described embodiment thereof, as alterationsand modifications may be made therein without departing from the spiritand full intended scope of the invention, as dened in the appendedclaims.

I claim:

1. In combination in a compressor of the type noted, a case structurehaving a compression chamber of elliptical section, a chamber inlet portlocated centrally of one sidenof the chamber,

va plate across the opposite side of the chamber,

characterized by parallel, graduated discharge apertures, an inlet portin said case near one end of the elliptical chamber, means disposedacross the last said port defining a plurality of parallel, iiatentering streams, a substantially curved passage formed in the case andconnecting said ports, the passage extending along one end and one sideof the chamber between said ports, and a baille member extending withina portion of said curved passage substantially perpendicular to theentering streams and inwardly of the case ports.

2. In combination in a compressor of Roots type, a case structureincluding a compression chamber therein, a chamber inlet portintermediate one side of the compression chamber, an inlet port in anouter end wall portion of said case, a passage of a tortuous trendconnecting said inlet port and extending over a substantial part of oneend and side of the compression chamber wall, and a grille elementtraversed by the impeller elements of the compressor and apertured toprovide a series of graduated outlet ports defining a plurality ofnon-intersecting dischargeber, and a plurality of passages ofsubstantially parallel trend and graduated area through the plate andconnecting said air compression chamber and tting.

4. The combination in a compressor of Roots type, of two groups ofcoacting impeller elements, a casing defining an internal displacementchamber for each group of said elements and an outer chamberconstituting separate air passages for supplying the groups of impellerelements, the 75 casing being provided with an inlet openings:A'substantial size directed into one end of 'each of the air supplypassages, a baille in each supply passages continuing from the bailletherein, in a curved path to a zone of air introduction to thedisplacement chambers, said zone being located centrally of one side ofthe displacement chamber structure. 1

5. 'I'he combination ina including two coacting impeller elements and acasing therefor, of a perforate plate constituting a casing wallextended across the discharge side of the blower,- said plate havinginner 'surface portions each adjacent to and traversed by one of theimpeller elements, each of said surface portions being provided with aseries of discharge passages of increasing sectional area toward thecenter of the plate, the plate being further provided with a centralpassage traversed in part by both impeller elements and of slightlygreater sectional area than the remaining passages, said passages beingparallel 4to each other and of a trend along the line of normal uiddischarge from the blower. Y

6. The combination, in a blower of Rootstype including two coactingimpeller elements and a casing therefor, of a perforate plateconstituting a casing wall extended across the discharge side of theblower, said plate having inner `surface portions :each adjacent t o andtraversed by one of the impeller elements, each of said surface blowerof Roots type.

, v3 portions being provided with a series of discharge passagesofincreasing "sectional area toward the center of the plate, the platebeing further provided with a -central e traversed in part by bothimpeller elements and of slightly greatersectional area than theremaining passages, said passages being parallel to each other` and of atrend along the line of normal fluid discharge from the blower, thewalls of the blower casing being extended laterally to form adischarge-airrecelving space, the extended walls being externallyflanged .for connection to an air receiver or machine to be suppliedbythe blower.

- 7. 'I'he combination, in a blower of Roots type including coactingimpeller elements and a casing therefor, of an outer chamber in thecasing constituting an air inlet passage Lprovided with an inlet openingof substantial size' directed into one outer end of the casing. a banleoverlying the inlet opening and spaced therefrom, a grille elementmounted near the inlet opening. the said inlet passage continuing fromthe baille to a zone of air introduction locate centrally of one side ofthe casing and remote rom said inlet opening,

a perforateplate bridgi the discharge side of the blower casing andhaving arcuate inner surface portions, one adjacent each impeller andtraversed thereby, each arcuate surface portion being provided with aseries of discharge passages of increasing sectional area toward thecenter .of the plate, said passages being substantially

